content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.impl.operators;
  
  import hu.akarnokd.reactive4javaflow.*;
  import hu.akarnokd.reactive4javaflow.functionals.CheckedPredicate;
  import hu.akarnokd.reactive4javaflow.fused.*;
  
  import java.util.concurrent.Flow;
  
  public final class EsetlegFilter<T> extends Esetleg<T> {
  
      final Esetleg<T> source;
  
      final CheckedPredicate<? super T> predicate;
  
      public EsetlegFilter(Esetleg<T> source, CheckedPredicate<? super T> predicate) {
          this.source = source;
          this.predicate = predicate;
      }
  
      @Override
      protected void subscribeActual(FolyamSubscriber<? super T> s) {
          source.subscribe(new FilterSubscriber<>(s, predicate));
      }
  
      static final class FilterSubscriber<T> implements FolyamSubscriber<T>, FusedSubscription<T> {
  
          final FolyamSubscriber<? super T> actual;
  
          final CheckedPredicate<? super T> predicate;
  
          FusedSubscription<T> qs;
  
          Flow.Subscription upstream;
  
          boolean done;
  
          FilterSubscriber(FolyamSubscriber<? super T> actual, CheckedPredicate<? super T> predicate) {
              this.actual = actual;
              this.predicate = predicate;
          }
  
  
          @Override
          public void onSubscribe(Flow.Subscription subscription) {
              upstream = subscription;
              if (subscription instanceof FusedSubscription) {
                  qs = (FusedSubscription<T>)subscription;
              }
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T item) {
              try {
                  if (!predicate.test(item)) {
                      return;
                  }
              } catch (Throwable ex) {
                  FolyamPlugins.handleFatal(ex);
                  done = true;
                  actual.onError(ex);
                  return;
              }
              actual.onNext(item);
          }
  
          @Override
          public void onError(Throwable throwable) {
              if (done) {
                  FolyamPlugins.onError(throwable);
              } else {
                  actual.onError(throwable);
              }
          }
  
          @Override
          public void onComplete() {
              if (!done) {
                  actual.onComplete();
              }
          }
  
          @Override
          public void request(long n) {
              upstream.request(n);
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
          }
  
          @Override
          public int requestFusion(int mode) {
              FusedSubscription<T> fs = qs;
              if (fs != null && (mode & BOUNDARY) == 0) {
                  return fs.requestFusion(mode);
              }
              return NONE;
          }
  
          @Override
          public T poll() throws Throwable {
              T v = qs.poll();
              if (v != null && predicate.test(v)) {
                  return v;
              }
              return null;
          }
  
          @Override
          public boolean isEmpty() {
              return qs.isEmpty();
          }
  
          @Override
          public void clear() {
              qs.clear();
          }
      }
  }
  